short story long: the account is easy enough to recreate. if you knew what his ID was before, maybe you could salvage the mail store files from /opt/zimbra/store using some sort of ext undeleted like extundelete: An ext3 and ext4 file undeletion utility . Ultimately all your structure would be gone though because the folder structure is stored in a db that was deleted too. so the best you could hope for would be to inject whatever emails you could recover straight into his recreated inbox

If you have a recent backup, I'd suggest recovering the system on a temporary machine (Virtual Machine for all intensive purposes), extract the data from his account on the temporary machine using the GetRestUrl, copy it over to your production server, and import it into his account using PostRestUrl.